Hi,

  In mail "Re: ruby smtp and gmail"
  Jan 'jast' Krueger <usenet / zoidberg.org> wrote:

> > /usr/local/lib/ruby/1.8/net/smtp.rb:680:in `check_response': 530 5.7.0
> > Must issue a STARTTLS command first (Net::SMTPUnknownError)
> 
> That means that the server requires an encrypted connection via TLS, and the
> SMTP module doesn't appear to support that (many less powerful clients don't).
> 
> Many other mail servers will accept your mails; only a select few actually
> *require* TLS/SSL (mine is among them ;)).
> 
> You might want to try setting up an SSL tunnel that locally encrypts things
> and sends them to the server's SMTPS port (465). This is probably easier to
> do outside Ruby, though.

net/smtp supports SMTPS in CVS HEAD.
It might work with Ruby 1.8.

Regards,
Minero Aoki